Colorectal cancer (CRC) has become the third most common cancer in developed countries. Each year more and more people die from CRC. CRC is also one of the most effectively studied topics in recent years. It has been found that the key phenomena in CRC development are genetic and inflammatory processes. Well-known genetic bases for the carcinogenesis of CRC include chromosomal changes characteristic of the chromosomal instability pathway which correlates with specific and well-defined genetic alterations (such as APC, K-RAS, DCC and p53) and genomic instability characteristics for the mutator pathway focused on KRAS and BRAF mutations. Recent studies have highlighted the impact of inflammation in CRC, especially elevated levels of pro-inflammatory cytokines. Among important risk factors of colon carcinogenesis are colorectal polyps, which are currently the subject of intense research. Recent studies have shown that different adenomas are characterized by different pathways of carcinogenesis as well as diverse COX-2 expression in various polyps. Understanding the mechanism of inflammatory processes in CRC parallel to basic genetic alterations might allow for effective and targeted treatment.